1. Field of the Invention
The present invention relates to a network monitoring device that monitors communication devices, or more particularly, to a network monitoring device for a system that accommodates many objects of management which have relatively low reliability compared with switching equipment, transmission equipment, or backbone communication equipment and which Include customer premises equipment (CPE), a femtocell base station, a Home Energy Management System (HEMS), a Worldwide Interoperability for Microwave Access (WiMAX) Wireless Fidelity (WiFi) router, and an onboard wireless repeater.
2. Description of the Related Art
In recent years, communication carriers have come to extensively introduce such facilities as a WiFi spot, a femtocell base station, and a WiFi mobile router to cope with a drastic increase in traffic due to prevalence of smartphones and mobile data communications. Data traffic in vehicles such as railroad trains is increasing, and building a WiFi access point is being encouraged as an off-road commitment to third-generation (3G) networks.
Further, optical access services have prevailed, and termination devices for optical access lines have come to exhibit high performance and cope with services of high value. Further, planning of providing electricity meters or the like with a capability of communication equipment and using the electricity meters as an infrastructure to support new services including a smart grid is in progress.
Specifically, the importance of relatively low-reliability and small-sized communications infrastructures such as the CPE, femtocell base station, HEMS, WiMAX router, WiFi router, and wireless repeater is thought to more and more grow.
The above low-reliability and small-sized communication devices have features that are described below and are different from those of high-reliability, large-scale, and high-availability communications infrastructures such as existing transmission equipment and switching equipment.
(1) Although each of the devices has a small size and a small capacity, the number of communication devices constituting a system is very large (it may reach several tens of thousands or several millions).
(2) Ceasing use of any of the devices for reasons only known to a device user or device installing person takes place daily. A network administrator cannot grasp or administer usages of all the devices.
In order to attract end users, communications carriers are laying weight on improvement of service quality, or more especially, improvement of communication quality. Noted is that the CPE refers to a premises device and encompasses a home gateway (HGW) and optical network unit (ONU).
Patent documents cited during prior-art search are JP-A-2002-024976 and JP-A-09-098167. JP-A-2002-024976 discloses an abnormality monitoring and reporting system in paragraphs 0019 and 0021 to 0025 and FIG. 1. Herein, the system includes central equipment and plural reporting terminals. Initial report data is transmitted from each of the reporting terminals to the central equipment. When any of the reporting terminals is designated as a terminal that is an object of no-communication state monitoring, an average report receiving interval and maximum report receiving Interval are calculated based on a reporting interval for previous report data in relation to each of the reporting terminals, preserved, and designated as a reference report receiving interval (comparable to a threshold). If a no-reporting time exceeds the reference report receiving interval, wireless reporting and monitoring information that includes device information with which the reporting terminal is identified is outputted in order to notify a monitoring person.